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Query: UMLS:C0002895 (sickle cell disease)
 11,747 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

New insights into the physical chemistry and molecular epidemiology of sickle cell anemia have improved our understanding of the pathophysiology of the associated nephropathy, the predictors of this complication, and genetic and other factors that may modify it. In this article, we analyze the current clinicopathologic knowledge with reference to the predilection to nephropathy and the protection from hypertension, as well as the altered renal physiology of the sickle cell state that underlies both these phenomena. In the early stages of sickle cell anemia, the kidney is characterized by impaired function of the renal medulla, as evidenced by reduced capacity to concentrate, acidify, and excrete potassium into the urine. Meanwhile, the cortex functions supranormally, as evidenced by increased renal plasma flow and glomerular filtration rate, proximal tubular function, and urinary diluting capacity. In addition to the complications of hematuria and papillary necrosis, renal insufficiency supervenes in a subgroup of patients. The morphology of the glomerulopathy generally differs between children and adults; in the latter group there is a particularly poor prognosis and markedly shortened life expectancy. Renal replacement therapy has nonetheless been successful. Although hypertension may be found at this stage, it is extremely rare before the onset of significant renal impairment. The possible mechanism of this protection is discussed, with a focus on the compelling need for further investigation in light of the newly gained basic understanding of this hematorenal syndrome.
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PMID:The kidney in sickle cell anemia. 157 59

Sickle cell disease is known to cause glomerulopathy, including focal segmental glomerulosclerosis (FSGS). Patients who have sickle cell glomerulopathy with FSGS are thought to have a poorer prognosis than patients who have sickle cell glomerulopathy without this lesion. The former patients are more likely to have persistent proteinuria and eventually develop end-stage renal disease. We present a boy with sickle cell glomerulopathy and FSGS who is younger than patients with similar findings reported previously. The histopathology of his renal lesions is remarkable for segmental ultrastructural changes in the glomerular basement membranes and endothelial cells. We speculate that these changes are precursory to the pathogenesis of glomerular sclerosis in patients with sickle cell disease.
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PMID:Sickle cell glomerulopathy with focal segmental glomerulosclerosis. 177 2

Of 240 adults with sickle cell anemia seen over 11 years, 12 had the nephrotic syndrome. In 9 (75%) the glomerular lesion, sickle glomerulopathy, consisted of mesangial expansion and basement membrane duplication. Six patients had type IV renal tubular acidosis. Four of the 9 Patients died within 24 months (17 +/- 5; mean +/- SD), while 5 survived 36 months or longer (80 +/- 49); no significant differences were seen between the former and the latter in age, admission serum creatinine and C3 levels, urinary protein excretion, or the frequency of renal tubular acidosis. Chronic azotemia developed in 3 and acute renal shutdown in another 2. Of 22 patients with sickle glomerulopathy (our 9 added to 13 from the literature) 11 died within 2 years. Ten of these (91%) had developed renal failure, compared to only 5 of the 11 (45%) who survived longer than 2 years (p less than 0.05). The 5-year mortality in the general population of sickle cell anemia is 3.75%, and 75% of patients aged 15 years or older survive 18 years or longer. The nephrotic syndrome, most often caused by sickle glomerulopathy, occurs in 4% of patients with sickle cell anemia, leading to renal failure in two-thirds and death in 2 years in half the patients. The development of chronic azotemia correlates strongly with early mortality. The prognosis is much worse than that in the general population of sickle cell anemia.
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PMID:Prognosis of the nephrotic syndrome in sickle glomerulopathy. A retrospective study. 360 31

The transgenic SAD mouse which expresses a modified sickle hemoglobin, Hb SAD, displays in vivo hemoglobin polymerization and erythrocyte sickling. In the presence study functional and morphological renal analyses were performed in SAD mice in order to compare the renal pathology of SAD mice with the human disease. The SAD mice display renal hemosiderosis, microvascular occlusions, vascular thrombosis, cortical infarcts and papillary necrosis. In the medulla, hemoglobin polymers could be observed with infrequent erythrocyte sickling, which may explain the absence of significant renal concentration defect, whereas in humans, the difference in the vascularization network leads to more extensive sickling. Most animals develop glomerular hypertrophy and mesangial sclerosis which increases in frequency and severity with age. The glomerular damage is associated with functional defects, including increased blood urea nitrogen levels and non-selective proteinuria. The glomerular lesions of SAD mice strikingly mimic sickle cell glomerulosclerosis, the most severe renal complication of sickle cell disease in humans. In summary, the SAD mouse is a valuable model of the thrombotic and glomerulosclerotic complications of human sickle cell glomerulopathy and can serve for pathophysiologic studies, and, eventually, for prevention and therapy investigation.
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PMID:The transgenic SAD mouse: a model of human sickle cell glomerulopathy. 785 92

Erythrocyte sickling on deoxygenation in vitro occurs in transgenic SAD mice, hemizygous for a modified human sickle hemoglobin, HbSAD [alpha 2 beta 2S(beta 6val)Antilles (beta 23 lle)D- Punjab (beta 121Gln)] (SAD-1, 19% HbSAD; beta-thal/SAD-1, 26% HbSAD). The present study examines the cellular defects in vivo and pathologic changes observed in SAD-1 mice at atmospheric oxygenation as well as the effect of acute hypoxia. The transgenic mice showed generalized congestion and microvascular occlusions, occasionally with thrombosis and infarctions of lung, kidneys, penis, and myocardium. The most prevalent chronic organ lesions were congestive splenomegaly (83% of animals) and renal glomerulopathy, which affected 75% of animals by 10 months of age. Further, SAD mice have a mean lifespan that was reduced by 40% when compared with nontransgenic littermates. Premature death of SAD mice was associated with acute vasoocclusive events or severe renal disease. SAD mice developed lethal vasoocclusive processes when exposed to reduced pO2 conditions, whereas control mice survived normally. The sensitivity to hypoxia appears to depend on the cellular level of HbSAD, because death occurred at pO2 of 42 mmHg for SAD mice and 49 mmHg for beta-thal/SAD. Administration of an antisickling agent that increases oxygen affinity (BW12C79) protected SAD and beta-thal/SAD mice from the lethal hypoxic stress. In conclusion, the transgenic SAD and beta-thal/SAD mice developed a pathophysiology that strongly resembles human sickle cell disease. Moreover, this animal model allows studies on the effect of antisickling agents.
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PMID:Sickle cell disease of transgenic SAD mice. 794 91

We studied kidney biopsy specimens from three children with sickle cell anemia and microangiopathic glomerulopathy. One child also had cyanotic congenital heart disease. Laboratory evaluation revealed proteinuria and normal serum creatinine in all and normal serum complement in two of the three children at the time of biopsy. In all biopsies, glomeruli were enlarged with diffuse hypercellularity and focal segmental mesangial interposition; capillary loop lumens were congested with sickled erythrocytes. Immune labeling identified segmental immunoglobulin G, C3, and properdin over the glomerular capillary loop walls in each case. Ultrastructurally, the subendothelial zone of the glomerular basement membrane was widened with new lamina densa formation with focal mesangial interposition. The glomerular lesion we describe in these children may be due to endothelial injury related to the altered erythrocytes, glomerular hemodynamics, and the hypercoagulable state characteristic of sickle cell disease.
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PMID:Microangiopathic glomerulopathy in children with sickle cell anemia. 902 33

We characterized glomerular function in adults with sickle cell anemia (SSA): 12 with normal renal function (SSA-controls), and 15 with renal insufficiency (SSA-CRF). GFR was similar in SSA-controls and healthy-controls, however, renal plasma flow was increased in SSA-controls. In SSA-CRF, the albumin and IgG excretion rates were enhanced. The fractional clearances of all dextran sizes (26 to 64 A) were significantly increased in both SSA-controls and SSA-CRF versus healthy-controls. In SSA-CRF, the fractional clearance of dextrans > 58 A was enhanced. Analysis with an "isoporous+shunt" model revealed an increase in the mean restrictive pore radius (ro) by 5 A in SSA-controls and SSA-CRF, versus healthy-controls. In SSA-CRF, the total number of membrane pores was reduced > 70%, and the shunt parameter increased twofold. We conclude that SSA patients have a distinct pattern of glomerular dysfunction with generalized increased permeability to dextrans, resulting from an increase in pore radius. When CRF develops, the total number of membrane pores is reduced, and a size-selectivity defect occurs. The changes in dextran permeability cannot be attributed to purely hemodynamic changes (increased RPF or low filtration fraction), or to known modulators of membrane porosity. These findings suggest that unique mechanism(s) are implicated in the pathogenesis of sickle glomerulopathy.
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PMID:Sickle cell anemia causes a distinct pattern of glomerular dysfunction. 906 17

There is a large variability in the severity of the clinical manifestations of sickle cell anemia (SSA), including renal involvement. Haplotypes in the beta-globin gene cluster associated with the geographical origin of the sickle mutation, as well as microdeletions in the alpha-globin genes, could provide an epigenetic influence on the heterogeneous outcome in SSA. It has been determined that the cause of progressive renal insufficiency in SSA is a glomerulopathy, clinically detected by the presence of macroalbuminuria (albumin excretion rate >300 mg/g creatinine). To investigate the role of the alpha-globin gene microdeletion and beta-globin gene cluster haplotypes on the degree of glomerular involvement, 76 adult SSA patients (hemoglobin SS) were studied to determine the relationship between these genetic markers and the development of sickle cell glomerulopathy. Macroalbuminuria was present in 22 (29%) of 76 adult SSA patients. The coinheritance of microdeletions in one or two of the four alpha-globin genes (alpha-thalassemia) was associated with a lower prevalence of macroalbuminuria (13%) versus patients with intact alpha-globin genes (40%, P = 0.01). By contrast, there was no association between albuminuria and beta-globin gene haplotypes (Central African Republic [CAR] versus non-CAR haplotypes). Patients with alpha-globin gene microdeletions had lower mean corpuscular volumes and mean corpuscular hemoglobin concentration than patients with all four alpha genes (86+/-2 versus 99+/-3 fl, and 33.9+/-0.2 versus 34.9+/-0.2%, respectively, P<0.05). There were no such hematologic differences between CAR and non-CAR beta-globin haplotypes. There were no differences in duration of disease (age), hemoglobin levels, reticulocyte index, and lactate dehydrogenase levels between those with and without glomerulopathy, but the mean arterial pressure was higher (87+/-1 mm Hg) in patients with intact alpha gene locus versus those with microdeletions (80+/-2 mm Hg, P<0.05). It is concluded that the coinheritance of microdeletions in the alpha-globin gene locus in SSA patients confers "renoprotection" by mechanisms not related to the degree of anemia or the severity of hemolysis, but could be related to a reduced mean corpuscular volume or to a lower erythrocyte hemoglobin concentration.
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PMID:Evidence that microdeletions in the alpha globin gene protect against the development of sickle cell glomerulopathy in humans. 1023 87

A 12-year-old African American male with homozygous sickle cell disease (SCD) was admitted with insidious onset of periorbital and scrotal edema. The initial evaluation failed to reveal any underlying monoclonal gammopathy, or cryoglobulinemia, or other systemic causes for the renal disease. A percutaneous renal biopsy was consistent with immunotactoid glomerulopathy (ITG), which is rare in children and is characterized histologically by fibrillar deposits in the glomeruli. Children can present with symptoms of nephrotic syndrome and progress to end stage renal disease. Our patient was treated with an ACE inhibitor and is currently free of edema and with normal renal function on follow-up at 1 year. Immunotactoid glomerulopathy should be considered in the differential diagnosis of nephrotic syndrome in children with sickle cell disease. Renal biopsy is indicated in children with sickle cell disease and nephrotic syndrome and ITG should be considered as potential cause. Although there is no effective treatment for this condition, ACE inhibitors can decrease the protein-uria and possibly delay the progression to end stage renal disease. The side effects related to the use of ACE inhibitors should be monitored. These include renal impairment, hyperkalemia, anemia, neutropenia, and angioedema. Since we have a short follow-up in our patient, the role and safety of ACE inhibitors in the management of ITG need further evaluation.
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PMID:Immunotactoid glomerulopathy in sickle cell anemia. 1119 11

For various ethnic and socioeconomic reasons the pattern of renal disease in the inner city displays distinctive features. Hypertension is frequent, often intractable, and generally conditioned by salt sensitivity and a high sodium intake. Chronic hypertensive nephrosclerosis, found predominantly in African Americans, comprises marked cardiomegaly, renal shrinkage, and hypertensive retinopathy. It has been overdiagnosed in the past, but actually accounts for less than 20% of end-stage renal disease (ESRD) in African Americans. Malignant hypertension, less frequent nowadays, may cause renal shutdown, which is reversible in a few cases; the heart and kidneys are often of normal size. Idiopathic focal segmental glomerulosclerosis is the most common cause of the primary nephrotic syndrome in blacks, but its incidence has also been rising in whites and Hispanics; it does not respond well to treatment, and almost one half of the patients develop ESRD within 10 years. Systemic lupus erythematosus is also more common in African Americans, in whom the severe proliferative forms of lupus nephritis pursue a more virulent course: one half of such patients develop ESRD in 5 years. Cocaine, the use of which has assumed epidemic proportions, may cause accelerated hypertension, acute renal failure from rhabdomyolysis, and progression of preexisting renal disease. Heroin nephropathy has all but disappeared and has been replaced by human immunodeficiency virus (HIV) nephropathy. The prognosis of HIV-infected patients maintained by dialysis has greatly improved. Sickle glomerulopathy, consisting of mesangial expansion, basement membrane duplication, and the absence of immune deposits, may cause the nephrotic syndrome in 4% of patients with severe sickle cell anemia, heralding death within 2 years in one half of patients and ESRD in two thirds; survival has not improved with dialysis. Diabetes is now the most common cause of ESRD. Familial aggregation of ESRD is frequently encountered. Interventions useful in the general population, such as vascular bypass procedures, should be undertaken with great caution and restraint in dialysis patients.
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PMID:Renal disease in the inner city. 1145 21


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